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1. rotational invariance
rotated by 0.5 degree about each axis
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psi4 in-built cubic grids
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sc, 2-stg: 0.002658
sc, wk. : 0.002016
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sc, 2-stg: 0.002320
sc, wk. : 0.002438
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sc, 2-stg: 0.002447
sc, wk. : 0.002644
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FCC grids
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fcc, 2-stg: 0.001405
fcc, wk. : 0.002363
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fcc, 2-stg: 0.000830
fcc, wk. : 0.001144
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fcc, 2-stg: 0.002252
fcc, wk. : 0.003460
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rotation by 0.5 (100 frames)
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rotation by 0.1 (100 frames)
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rotation by 0.1 (500 frames)
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rotation by 0.05 (100 frames)
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psi4 in-built cubic grids
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sc, 2-stg: 0.002447
sc, wk. : 0.002644
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sc, 2-stg: 0.001717
sc, wk. : 0.002277
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sc, 2-stg: 0.001902
sc, wk. : 0.002425
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FCC grids
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fcc, 2-stg: 0.002252
fcc, wk. : 0.003460
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fcc, 2-stg: 0.001396
fcc, wk. : 0.001372
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fcc, 2-stg: 0.001153
fcc, wk. : 0.001251
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Psi4 inputs for different grid generation schemes
When using Psi4’s in-built cubic grid
| Code Block |
|---|
set cubeprop_tasks ['esp']
set cubic_grid_spacing [1.1785, 1.1785, 1.1785]
set cubic_grid_overage [8.0, 8.0, 8.0] # size of the cubic grid (default = 4 Bohr)
e, wfn = energy('HF', return_wfn=True)
cubeprop(wfn) |
When using a user-specified grid points specified in
grid.dat(should be located in the same directory with Psi4 input)
| Code Block |
|---|
E,wfn = prop('HF' , properties = ['GRID_ESP'], return_wfn=True) |
* Generation of FCC grid used for charge fitting
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(1) Generate a box containing the molecule and fill it with FCC grid pts;
(2) Select grid points which are inside the outer boundary and outside the inner boundary (a shell of points);
(3) Store selected points to grid.dat
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1. rotational invariance
Procedure:
(1) Rotated a test molecule(MeOH) by multiples of 0.5 degree about an axis (100 frames)
(2) Generated both cubic grid(using Psi4 in-built feature) and FCC grid, ran ESP generation on each grid, for cubic grid, selected points using the same outer and inner boundary with FCC grids and used for charge fitting.
(3) RESP two stage fit charges were calculated from each frame and calculated standard deviation of charges.
psi4 in-built cubic grids | 0.001852 | 0.001895 | 0.004404 |
FCC grids | 0.001405 | 0.000830 | 0.002252 |
2. transitional invariance
psi4 in-built cubic grids | sc, 2-stg: 0.000379 sc, wk. : 0.000074 000174 |
FCC grids | fcc, 2-stg: 0.000644 fcc, wk. : 0.000393 |